Lightning strikes are desirable to protect against, including with respect to aircraft. One method of warning of an imminent lightning strike includes measuring the strength of an electric field.
One approach in the prior art has included using electric field mills which include a spinning set of fan blades that alternately cover and uncover an anode plate that is alternately charged by the electric field when uncovered and the charge state determined followed by discharge of the anode plate when covered.
While an electric field mill gives a good absolute measure of an electric field, an electric field mill includes moving parts, such as a high rpm motor (e.g., 1650 rpm) and two metallic coaxial disks separated by a fixed distance, and therefore has the drawbacks of being bulky, complex, and sensitive to stress and wear, requiring frequent servicing.
Accordingly there is a need for an electric field sensor that overcomes at least some of the drawbacks of prior art field sensors e.g., is smaller, has few or no moving parts, and requires less or infrequent servicing.